Fractured Abutment: tips for removing without damaging implant?
I have a patient with an 8-year old Zimmer Advent Bar Overdenture. The overdenture bar fractured and a portion of the abutment is still in the implant fixture. Does anybody have any clinical tips for removing the abutment without damaging the implant internal threads? The first photograph shows the fractured abutment that the bar was screwed into. The second photograph shows the new Locator single abutment that only screws in ~ 3 threads into the old abutment. Therefore the old abutment needs to be removed. Grateful for any help.
Fractured Abutment inside Advent
New Locator Abutment Only Screws into old Abutment ~ 3 Threads
14 Comments on Fractured Abutment: tips for removing without damaging implant?
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CRS
1/23/2014
What do you think is fractured off in the implant? Perhaps the screw? Could be time for a new bar and prosthesis checking the intra arch space and occlusion, I don't think a locator can be used with a bar?
IRWE
1/23/2014
The cantilever portion of the bar fractured off. I plan on converting this portion to a single implant locator once fractured bar abutment is removed and the remaining 3 implants will support the rest of the bar.
Jon
1/23/2014
Is there a screw retaining that abutment? They make screw removal kits. Also, we have a local endodontist that is an expert getting these screws out (if conventional ways fail) using the microscope and very small burs.
IRWE
1/23/2014
Yes, there is a fractured screw inside and the abutment is 'cold welded' with the Morse taper connection.
Carlos Boudet, DDS DICOI
1/30/2014
There is no morse taper in a Zimmer Advent implant. The internal hex has a "friction fit that helps hold the abutment in after the screw has been tightened.
To restore with a bar, it can be done with
1- a bar gold coping, or
2- a tapered abutment
If you want to research this, here is a pdf that shows you the parts and the prosthetic sequence:
From your pictures, it looks like you have a tapered abutment with a broken abutment screw.
Before spending your money in expensive kits, try the simpler solutions first as suggested above backing out the screw.
I made a video of the procedure if you want to see it, it's posted in youtube here:
http://www.youtube.com/watch?v=d8jB-30Uop8
I hope it's ok to post the link.
Remove the screw and replace the bar or redesign the case as you see fit.
Good luck!
kim
1/23/2014
try making a "slot" on the abutment and use a flat screw driver to turn it and break the "cold weld."
IRWE
1/24/2014
Yes, this approach sounds reasonable. I will first try piezo to loosen and back out the broken screw then make a slot on the abutment and see if a small flat head screw driver will back it out.
The pt is in next week and I will try and take some photo's and post.
k
1/24/2014
if all else fails, you can always cut the abutment completely off of body of implant. of course, this is very labor intensive and a very delicate procedure because you have to only cut the abutment and not damage the moris taper part of the implant, but it is guaranteed to work.
Richard Hughes, DDS, FAAI
1/24/2014
Worst case situation, make a new bar and prep this implant and cement the bar to this implant. Try using an ultrasonic scaler to back out the screw. The other Docs gave good advice.
The bar fractured for a reason such as: 1) bruxing; 2) contaminats in the metal coasted; 3) poor casting technique.
Use a milled bar, if you have enough VDO.
Vladimir
1/25/2014
If nothing helps, There are universal screw removal kit from Neobiotech , you can easy remove any broken screw .
IRWE
1/25/2014
The bar fractured because the distal portion of the bar in this area was cantilevered with a cast locator attachment on top of the bar. Even opposing a Complete Upper Denture there was enough force to fracture it over time.
Darius
1/26/2014
I try to unscrew the fractured part of screw with probe with shap tip. And it goes out very easy and fast. If the fractured surface is all flat then you can't use this method. You can then try screw removal kits.
John L Manuel, DDS
1/28/2014
I am guessing this implant has both a screw and taper mounted abutment? Is the screw engaging the implant body? ...or is the screw in a short abutment held only by a taper? In the Bicon taper lock implants, one could release the "cold weld" portion by carefully hollowing out the center core of the tapered post and then even a slow, round bur run backward would knock the cold weld loose.
If the problem is a screw then cutting the slot and trying to turn out might work, but it's tough to keep from damaging the threads. Even with a screw, hollowing out the center will often loosen the outside, engaged threads.
Alok bhardwaj mds
1/28/2014
Try using an ultrasonic scaler tip for approx 3-5 min. This Loosen's the cold weld easier.
